This invention relates to a method of determining alveolar ventilation, carbon dioxide production and oxygen uptake. More particularly, this invention relates to a non-airtight method of determining the volume of alveolar gases and of carbon dioxide production and oxygen uptake of a human being.
Existing methods for making measurement of oxygen uptake and carbon dioxide production require an airtight connection to the patient for monitoring expired gas volume and concentration. In most cases an airtight seal in the form of a mask or nosepiece interconnects the patient with a bag, spirometer or other collection device from which the volume of gas can be measured and the concentration of oxygen and carbon dioxide determined.
Many patients, particularly infants and young children, will not tolerate such obtrusive interfacing to the monitoring equipment. In order to avoid direct interfacing to a patient other methods have been devised. One such method involves keeping a patient in a sealed box so there can be no undetected escape of expired gas. This method is bulky and too expensive to use for practical purposes other than as a research tool.
There are various methods used for collecting alveolar gas and determining its contents but all are dependent upon an airtight connection to the patient.